Dynamically loaded editor used as a developer dependcy in https://github.com/SharePoint/sp-dev-fx-webparts/tree/master/samples/react-script-editor.
When installed with npm i sharepoint-modern-script-editor-propertypane --save-dev in a SharePoint Framework project a gulp task is added to gulpfile.js which will bundle the editor as a dynamic dependency.
Author: Mikael Svenson - 2018